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Qin Y, Xiao Z, Zhao H, Wang J, Wang Y, Qiu F. Starch phosphorylase 2 is essential for cellular carbohydrate partitioning in maize. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1755-1769. [PMID: 35796344 DOI: 10.1111/jipb.13328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Carbohydrate partitioning is essential for plant growth and development, and its hindrance will result in excess accumulation of carbohydrates in source tissues. Most of the related mutants in maize (Zea mays L.) display impaired whole-plant sucrose transport, but other mechanisms affecting carbohydrate partitioning have seldom been reported. Here, we characterized chlorotic leaf3 (chl3), a recessive mutation causing leaf chlorosis with starch accumulation excessively in bundle sheath chloroplasts, suggesting that chl3 is defective in carbohydrate partitioning. Positional cloning revealed that the chl3 phenotype results from a frameshift mutation in ZmPHOH, which encodes starch phosphorylase 2. Two mutants in ZmPHOH exhibited the same phenotype as chl3, and both alleles failed to complement the chl3 mutant phenotype in an allelism test. Inactivation of ZmPHOH in chl3 leaves reduced the efficiency of transitory starch conversion, resulting in increased leaf starch contents and altered carbohydrate metabolism patterns. RNA-seq revealed the transcriptional downregulation of genes related to photosynthesis and carbohydrate metabolism in chl3 leaves compared to the wild type. Our results demonstrate that transitory starch remobilization is very important for cellular carbohydrate partitioning in maize, in which ZmPHOH plays an indispensable role.
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Affiliation(s)
- Yao Qin
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ziyi Xiao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hailiang Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jing Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuanru Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Fazhan Qiu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
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2
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Julius BT, McCubbin TJ, Mertz RA, Baert N, Knoblauch J, Grant DG, Conner K, Bihmidine S, Chomet P, Wagner R, Woessner J, Grote K, Peevers J, Slewinski TL, McCann MC, Carpita NC, Knoblauch M, Braun DM. Maize Brittle Stalk2-Like3, encoding a COBRA protein, functions in cell wall formation and carbohydrate partitioning. THE PLANT CELL 2021; 33:3348-3366. [PMID: 34323976 PMCID: PMC8505866 DOI: 10.1093/plcell/koab193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/16/2021] [Indexed: 05/14/2023]
Abstract
Carbohydrate partitioning from leaves to sink tissues is essential for plant growth and development. The maize (Zea mays) recessive carbohydrate partitioning defective28 (cpd28) and cpd47 mutants exhibit leaf chlorosis and accumulation of starch and soluble sugars. Transport studies with 14C-sucrose (Suc) found drastically decreased export from mature leaves in cpd28 and cpd47 mutants relative to wild-type siblings. Consistent with decreased Suc export, cpd28 mutants exhibited decreased phloem pressure in mature leaves, and altered phloem cell wall ultrastructure in immature and mature leaves. We identified the causative mutations in the Brittle Stalk2-Like3 (Bk2L3) gene, a member of the COBRA family, which is involved in cell wall development across angiosperms. None of the previously characterized COBRA genes are reported to affect carbohydrate export. Consistent with other characterized COBRA members, the BK2L3 protein localized to the plasma membrane, and the mutants condition a dwarf phenotype in dark-grown shoots and primary roots, as well as the loss of anisotropic cell elongation in the root elongation zone. Likewise, both mutants exhibit a significant cellulose deficiency in mature leaves. Therefore, Bk2L3 functions in tissue growth and cell wall development, and this work elucidates a unique connection between cellulose deposition in the phloem and whole-plant carbohydrate partitioning.
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Affiliation(s)
- Benjamin T Julius
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
- Bayer Crop Science, Chesterfield, Missouri 63017, USA
| | - Tyler J McCubbin
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Rachel A Mertz
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
- Present address: Inari Agriculture, West Lafayette, Indiana 47906, USA
| | - Nick Baert
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Jan Knoblauch
- School of Biological Sciences, Washington State University, Pullman, Washington 99164, USA
| | - DeAna G Grant
- Electron Microscopy Core Facility, University of Missouri, Columbia, Missouri 65211, USA
| | - Kyle Conner
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Saadia Bihmidine
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Paul Chomet
- NRGene Inc., 8910 University Center Lane, San Diego, California 92122, USA
| | - Ruth Wagner
- Bayer Crop Science, Chesterfield, Missouri 63017, USA
| | - Jeff Woessner
- Bayer Crop Science, Chesterfield, Missouri 63017, USA
| | - Karen Grote
- Bayer Crop Science, Chesterfield, Missouri 63017, USA
| | | | | | - Maureen C McCann
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Nicholas C Carpita
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, Washington 99164, USA
| | - David M Braun
- Divisions of Plant Science and Technology, Biological Sciences, Interdisciplinary Plant Group, and the Missouri Maize Center, University of Missouri, Columbia, Missouri 65211, USA
- Author for correspondence:
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3
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Abstract
Auxin is an endogenous small molecule with an incredibly large impact on growth and development in plants. Movement of auxin between cells, due to its negative charge at most physiological pHs, strongly relies on families of active transporters. These proteins import auxin from the extracellular space or export it into the same. Mutations in these components have profound impacts on biological processes. Another transport route available to auxin, once the substance is inside the cell, are plasmodesmata connections. These small channels connect the cytoplasms of neighbouring plant cells and enable flow between them. Interestingly, the biological significance of this latter mode of transport is only recently starting to emerge with examples from roots, hypocotyls and leaves. The existence of two transport systems provides opportunities for reciprocal cross-regulation. Indeed, auxin levels influence proteins controlling plasmodesmata permeability, while cell-cell communication affects auxin biosynthesis and transport. In an evolutionary context, transporter driven cell-cell auxin movement and plasmodesmata seem to have evolved around the same time in the green lineage. This highlights a co-existence from early on and a likely functional specificity of the systems. Exploring more situations where auxin movement via plasmodesmata has relevance for plant growth and development, and clarifying the regulation of such transport, will be key aspects in coming years.This article has an associated Future Leader to Watch interview with the author of the paper.
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Affiliation(s)
- Andrea Paterlini
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1 LR, UK
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4
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Tran TM, McCubbin TJ, Bihmidine S, Julius BT, Baker RF, Schauflinger M, Weil C, Springer N, Chomet P, Wagner R, Woessner J, Grote K, Peevers J, Slewinski TL, Braun DM. Maize Carbohydrate Partitioning Defective33 Encodes an MCTP Protein and Functions in Sucrose Export from Leaves. MOLECULAR PLANT 2019; 12:1278-1293. [PMID: 31102785 DOI: 10.1016/j.molp.2019.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 04/09/2019] [Accepted: 05/03/2019] [Indexed: 05/29/2023]
Abstract
To sustain plant growth, development, and crop yield, sucrose must be transported from leaves to distant parts of the plant, such as seeds and roots. To identify genes that regulate sucrose accumulation and transport in maize (Zea mays), we isolated carbohydrate partitioning defective33 (cpd33), a recessive mutant that accumulated excess starch and soluble sugars in mature leaves. The cpd33 mutants also exhibited chlorosis in the leaf blades, greatly diminished plant growth, and reduced fertility. Cpd33 encodes a protein containing multiple C2 domains and transmembrane regions. Subcellular localization experiments showed the CPD33 protein localized to plasmodesmata (PD), the plasma membrane, and the endoplasmic reticulum. We also found that a loss-of-function mutant of the CPD33 homolog in Arabidopsis, QUIRKY, had a similar carbohydrate hyperaccumulation phenotype. Radioactively labeled sucrose transport assays showed that sucrose export was significantly lower in cpd33 mutant leaves relative to wild-type leaves. However, PD transport in the adaxial-abaxial direction was unaffected in cpd33 mutant leaves. Intriguingly, transmission electron microscopy revealed fewer PD at the companion cell-sieve element interface in mutant phloem tissue, providing a possible explanation for the reduced sucrose export in mutant leaves. Collectively, our results suggest that CPD33 functions to promote symplastic transport into sieve elements.
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Affiliation(s)
- Thu M Tran
- Division of Biological Sciences, Interdisciplinary Plant Group, Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA; Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA; National Key Laboratory for Plant Cell Technology, Agricultural Genetics Institute, Hanoi, Vietnam
| | - Tyler J McCubbin
- Division of Biological Sciences, Interdisciplinary Plant Group, Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA; Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Saadia Bihmidine
- Division of Biological Sciences, Interdisciplinary Plant Group, Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA
| | - Benjamin T Julius
- Division of Biological Sciences, Interdisciplinary Plant Group, Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA
| | - R Frank Baker
- Division of Biological Sciences, Interdisciplinary Plant Group, Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA
| | - Martin Schauflinger
- Electron Microscopy Core Facility, University of Missouri, Columbia, MO 65211, USA
| | - Clifford Weil
- Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA
| | - Nathan Springer
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, MN 55108, USA
| | - Paul Chomet
- NRGene Inc., 8910 University Center Lane, ∖r∖nSuite 400, San Diego, CA 92122, USA
| | - Ruth Wagner
- Bayer Crop Science, Chesterfield, MO 63017, USA
| | | | - Karen Grote
- Bayer Crop Science, Chesterfield, MO 63017, USA
| | | | | | - David M Braun
- Division of Biological Sciences, Interdisciplinary Plant Group, Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA.
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5
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Han X, Huang LJ, Feng D, Jiang W, Miu W, Li N. Plasmodesmata-Related Structural and Functional Proteins: The Long Sought-After Secrets of a Cytoplasmic Channel in Plant Cell Walls. Int J Mol Sci 2019; 20:ijms20122946. [PMID: 31212892 PMCID: PMC6627144 DOI: 10.3390/ijms20122946] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/29/2022] Open
Abstract
Plant cells are separated by cellulose cell walls that impede direct cell-to-cell contact. In order to facilitate intercellular communication, plant cells develop unique cell-wall-spanning structures termed plasmodesmata (PD). PD are membranous channels that link the cytoplasm, plasma membranes, and endoplasmic reticulum of adjacent cells to provide cytoplasmic and membrane continuity for molecular trafficking. PD play important roles for the development and physiology of all plants. The structure and function of PD in the plant cell walls are highly dynamic and tightly regulated. Despite their importance, plasmodesmata are among the few plant cell organelles that remain poorly understood. The molecular properties of PD seem largely elusive or speculative. In this review, we firstly describe the general PD structure and its protein composition. We then discuss the recent progress in identification and characterization of PD-associated plant cell-wall proteins that regulate PD function, with particular emphasis on callose metabolizing and binding proteins, and protein kinases targeted to and around PD.
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Affiliation(s)
- Xiao Han
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China.
| | - Li-Jun Huang
- College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China.
| | - Dan Feng
- Biotechnology Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China.
| | - Wenhan Jiang
- College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China.
| | - Wenzhuo Miu
- College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China.
| | - Ning Li
- State Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University of Forestry and Technology, Changsha 410004, China.
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6
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Julius BT, Slewinski TL, Baker RF, Tzin V, Zhou S, Bihmidine S, Jander G, Braun DM. Maize Carbohydrate partitioning defective1 impacts carbohydrate distribution, callose accumulation, and phloem function. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3917-3931. [PMID: 29846660 PMCID: PMC6054164 DOI: 10.1093/jxb/ery203] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/18/2018] [Indexed: 05/19/2023]
Abstract
Plants synthesize carbohydrates in photosynthetic tissues, with the majority of plants transporting sucrose to non-photosynthetic tissues to sustain growth and development. While the anatomical, biochemical, and physiological processes regulating sucrose long-distance transport are well characterized, little is known concerning the genes controlling whole-plant carbohydrate partitioning. To identify loci influencing carbon export from leaves, we screened mutagenized maize plants for phenotypes associated with reduced carbohydrate transport, including chlorosis and excessive starch and soluble sugars in leaves. Carbohydrate partitioning defective1 (Cpd1) was identified as a semi-dominant mutant exhibiting these phenotypes. Phloem transport experiments suggested that the hyperaccumulation of starch and soluble sugars in the Cpd1/+ mutant leaves was due to inhibited sucrose export. Interestingly, ectopic callose deposits were observed in the phloem of mutant leaves, and probably underlie the decreased transport. In addition to the carbohydrate hyperaccumulation phenotype, Cpd1/+ mutants overaccumulate benzoxazinoid defense compounds and exhibit increased tolerance when attacked by aphids. However, double mutant studies between Cpd1/+ and benzoxazinoid-less plants indicate that the ectopic callose and carbon hyperaccumulation are independent of benzoxazinoid production. Based on the formation of callose occlusions in the developing phloem, we hypothesize that the cpd1 gene functions early in phloem development, thereby impacting whole-plant carbohydrate partitioning.
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Affiliation(s)
- Benjamin T Julius
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
| | - Thomas L Slewinski
- Department of Biology, Pennsylvania State University, State College, PA, USA
| | - R Frank Baker
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
| | - Vered Tzin
- Boyce Thompson Institute, Ithaca, NY, USA
| | | | - Saadia Bihmidine
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
| | | | - David M Braun
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
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7
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Liesche J. Sucrose transporters and plasmodesmal regulation in passive phloem loading. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:311-321. [PMID: 28429873 DOI: 10.1111/jipb.12548] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 06/07/2023]
Abstract
An essential step for the distribution of carbon throughout the whole plant is the loading of sugars into the phloem in source organs. In many plants, accumulation of sugars in the sieve element-companion cell (SE-CC) complex is mediated and regulated by active processes. However, for poplar and many other tree species, a passive symplasmic mechanism of phloem loading has been proposed, characterized by symplasmic continuity along the pre-phloem pathway and the absence of active sugar accumulation in the SE-CC complex. A high overall leaf sugar concentration is thought to enable diffusion of sucrose into the phloem. In this review, we critically evaluate current evidence regarding the mechanism of passive symplasmic phloem loading, with a focus on the potential influence of active sugar transport and plasmodesmal regulation. The limited experimental data, combined with theoretical considerations, suggest that a concomitant operation of passive symplasmic and active phloem loading in the same minor vein is unlikely. However, active sugar transport could well play an important role in how passively loading plants might modulate the rate of sugar export from leaves. Insights into the operation of this mechanism has direct implications for our understanding of how these plants utilize assimilated carbon.
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Affiliation(s)
- Johannes Liesche
- College of Life Science, Northwest A&F University, No 3 Taicheng Road, Yangling 712100, China
- Biomass Energy Center for Arid and Semi-arid lands, Northwest A&F University, Yangling 712100, China
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8
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Baker RF, Leach KA, Boyer NR, Swyers MJ, Benitez-Alfonso Y, Skopelitis T, Luo A, Sylvester A, Jackson D, Braun DM. Sucrose Transporter ZmSut1 Expression and Localization Uncover New Insights into Sucrose Phloem Loading. PLANT PHYSIOLOGY 2016; 172:1876-1898. [PMID: 27621426 PMCID: PMC5100798 DOI: 10.1104/pp.16.00884] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/08/2016] [Indexed: 05/18/2023]
Abstract
Sucrose transporters (SUTs) translocate sucrose (Suc) across cellular membranes, and in eudicots, multiple SUTs are known to function in Suc phloem loading in leaves. In maize (Zea mays), the Sucrose Transporter1 (ZmSut1) gene has been implicated in Suc phloem loading based upon RNA expression in leaves, electrophysiological experiments, and phenotypic analysis of zmsut1 mutant plants. However, no previous studies have examined the cellular expression of ZmSut1 RNA or the subcellular localization of the ZmSUT1 protein to assess the gene's hypothesized function in Suc phloem loading or to evaluate its potential roles, such as phloem unloading, in nonphotosynthetic tissues. To this end, we performed RNA in situ hybridization experiments, promoter-reporter gene analyses, and ZmSUT1 localization studies to elucidate the cellular expression pattern of the ZmSut1 transcript and protein. These data showed that ZmSut1 was expressed in multiple cell types throughout the plant and indicated that it functions in phloem companion cells to load Suc and also in other cell types to retrieve Suc from the apoplasm to prevent its accumulation and loss to the transpiration stream. Additionally, by comparing a phloem-mobile tracer with ZmSut1 expression, we determined that developing maize leaves dynamically switch from symplasmic to apoplasmic phloem unloading, reconciling previously conflicting reports, and suggest that ZmSut1 does not have an apparent function in either unloading process. A model for the dual roles for ZmSut1 function (phloem loading and apoplasmic recycling), Sut1 evolution, and its possible use to enhance Suc export from leaves in engineering C3 grasses for C4 photosynthesis is discussed.
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Affiliation(s)
- R Frank Baker
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Kristen A Leach
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Nathanial R Boyer
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Michael J Swyers
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Yoselin Benitez-Alfonso
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Tara Skopelitis
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Anding Luo
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - Anne Sylvester
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - David Jackson
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.)
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
| | - David M Braun
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri 65211 (R.F.B., K.A.L., N.R.B., M.J.S., D.M.B.);
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 (Y.B.-A., T.S., D.J.); and
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071 (A.L., A.S.)
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9
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Griffiths CA, Paul MJ, Foyer CH. Metabolite transport and associated sugar signalling systems underpinning source/sink interactions. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1857:1715-25. [PMID: 27487250 PMCID: PMC5001786 DOI: 10.1016/j.bbabio.2016.07.007] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 06/06/2016] [Accepted: 07/23/2016] [Indexed: 11/19/2022]
Abstract
Metabolite transport between organelles, cells and source and sink tissues not only enables pathway co-ordination but it also facilitates whole plant communication, particularly in the transmission of information concerning resource availability. Carbon assimilation is co-ordinated with nitrogen assimilation to ensure that the building blocks of biomass production, amino acids and carbon skeletons, are available at the required amounts and stoichiometry, with associated transport processes making certain that these essential resources are transported from their sites of synthesis to those of utilisation. Of the many possible posttranslational mechanisms that might participate in efficient co-ordination of metabolism and transport only reversible thiol-disulphide exchange mechanisms have been described in detail. Sucrose and trehalose metabolism are intertwined in the signalling hub that ensures appropriate resource allocation to drive growth and development under optimal and stress conditions, with trehalose-6-phosphate acting as an important signal for sucrose availability. The formidable suite of plant metabolite transporters provides enormous flexibility and adaptability in inter-pathway coordination and source-sink interactions. Focussing on the carbon metabolism network, we highlight the functions of different transporter families, and the important of thioredoxins in the metabolic dialogue between source and sink tissues. In addition, we address how these systems can be tailored for crop improvement.
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Affiliation(s)
- Cara A Griffiths
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Matthew J Paul
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Christine H Foyer
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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10
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Wu J, Zhang Z, Zhang Q, Han X, Gu X, Lu T. The molecular cloning and clarification of a photorespiratory mutant, oscdm1, using enhancer trapping. Front Genet 2015; 6:226. [PMID: 26191072 PMCID: PMC4490251 DOI: 10.3389/fgene.2015.00226] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/15/2015] [Indexed: 01/08/2023] Open
Abstract
Enhancer trap systems have been demonstrated to increase the effectiveness of gene identification in rice. In this study, a chlorophyll-deficient mutant, named oscdm1, was screened and characterized in detail from a T-DNA enhancer-tagged population. The oscdm1 plants were different from other chlorophyll-deficient mutants; they produced chlorotic leaves at the third leaf stage, which gradually died with further growth of the plants. However, the oscdm1 plants were able to survive exposure to elevated CO2 levels, similar to photorespiratory mutants. An analysis of the T-DNA flanking sequence in the oscdm1 plants showed that the T-DNA was inserted into the promoter region of a serine hydroxymethyltransferase (SHMT) gene. OsSHMT1 is a key enzyme that is ubiquitous in nature and structurally conserved across kingdoms. The enzyme is responsible for the interconversion of serine and glycine and is essential for cellular one-carbon metabolism. Full-length OsSHMT1 complemented the oscdm1 phenotype, and the downregulation of OsSHMT1 in wild-type plants by RNA interference (RNAi) produced plants that mimicked the oscdm1 phenotype. GUS assays and quantitative PCR revealed the preferential expression of OsSHMT1 in young leaves. TEM revealed serious damage to the thylakoid membrane in oscdm1 chloroplasts. The oscdm1 plants showed more extensive damage than wild type using an IMAGING-PAM fluorometer, especially under high light intensities. OsSHMT1-GFP localized exclusively to mitochondria. Further analysis revealed that the H2O2 content in the oscdm1 plants was twice that in wild type at the fourth leaf stage. This suggests that the thylakoid membrane damage observed in the oscdm1 plants was caused by excessive H2O2. Interestingly, OsSHMT1-overexpressing plants exhibited increased photosynthetic efficiency and improved plant productivity. These results lay the foundation for further study of the OsSHMT1 gene and will help illuminate the functional role of OsSHMT1 in photorespiration in rice.
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Affiliation(s)
- Jinxia Wu
- Biotechnology Research Institute/National Key Facility for Genetic Resources and Gene Improvement, The Chinese Academy of Agricultural Sciences Beijing, China
| | - Zhiguo Zhang
- Biotechnology Research Institute/National Key Facility for Genetic Resources and Gene Improvement, The Chinese Academy of Agricultural Sciences Beijing, China
| | - Qian Zhang
- Biotechnology Research Institute/National Key Facility for Genetic Resources and Gene Improvement, The Chinese Academy of Agricultural Sciences Beijing, China
| | - Xiao Han
- Biotechnology Research Institute/National Key Facility for Genetic Resources and Gene Improvement, The Chinese Academy of Agricultural Sciences Beijing, China
| | - Xiaofeng Gu
- Biotechnology Research Institute/National Key Facility for Genetic Resources and Gene Improvement, The Chinese Academy of Agricultural Sciences Beijing, China
| | - Tiegang Lu
- Biotechnology Research Institute/National Key Facility for Genetic Resources and Gene Improvement, The Chinese Academy of Agricultural Sciences Beijing, China
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Knox JP, Benitez-Alfonso Y. Roles and regulation of plant cell walls surrounding plasmodesmata. CURRENT OPINION IN PLANT BIOLOGY 2014; 22:93-100. [PMID: 25286000 DOI: 10.1016/j.pbi.2014.09.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/16/2014] [Accepted: 09/20/2014] [Indexed: 05/28/2023]
Abstract
In plants, the intercellular transport of simple and complex molecules can occur symplastically through plasmodesmata. These are membranous channels embedded in cell walls that connect neighbouring cells. The properties of the cell walls surrounding plasmodesmata determine their transport capacity and permeability. These cell wall micro-domains are enriched in callose and have a characteristic pectin distribution. Cell wall modifications, leading to changes in plasmodesmata structure, have been reported to occur during development and in response to environmental signals. Cell wall remodelling enzymes target plasmodesmata to rapidly control intercellular communication in situ. Here we describe current knowledge on the composition of cell walls at plasmodesmata sites and on the proteins and signals that modify cell walls to regulate plasmodesmata aperture.
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Affiliation(s)
- J Paul Knox
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Yoselin Benitez-Alfonso
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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12
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Braun DM, Wang L, Ruan YL. Understanding and manipulating sucrose phloem loading, unloading, metabolism, and signalling to enhance crop yield and food security. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1713-35. [PMID: 24347463 DOI: 10.1093/jxb/ert416] [Citation(s) in RCA: 238] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Sucrose is produced in, and translocated from, photosynthetically active leaves (sources) to support non-photosynthetic tissues (sinks), such as developing seeds, fruits, and tubers. Different plants can utilize distinct mechanisms to transport sucrose into the phloem sieve tubes in source leaves. While phloem loading mechanisms have been extensively studied in dicot plants, there is less information about phloem loading in monocots. Maize and rice are major dietary staples, which have previously been proposed to use different cellular routes to transport sucrose from photosynthetic cells into the translocation stream. The anatomical, physiological, and genetic evidence supporting these conflicting hypotheses is examined. Upon entering sink cells, sucrose often is degraded into hexoses for a wide range of metabolic and storage processes, including biosynthesis of starch, protein, and cellulose, which are all major constituents for food, fibre, and fuel. Sucrose, glucose, fructose, and their derivate, trehalose-6-phosphate, also serve as signalling molecules to regulate gene expression either directly or through cross-talk with other signalling pathways. As such, sugar transport and metabolism play pivotal roles in plant development and realization of crop yield that needs to be increased substantially to meet the projected population demand in the foreseeable future. This review will discuss the current understanding of the control of carbon partitioning from the cellular to whole-plant levels, focusing on (i) the pathways employed for phloem loading in source leaves, particularly in grasses, and the routes used in sink organs for phloem unloading; (ii) the transporter proteins responsible for sugar efflux and influx across plasma membranes; and (iii) the key enzymes regulating sucrose metabolism, signalling, and utilization. Examples of how sugar transport and metabolism can be manipulated to improve crop productivity and stress tolerance are discussed.
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Affiliation(s)
- David M Braun
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO 65211, USA
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